Casting machine



H. WETZLER CASTING MACHINE Nov. 5, 1929.

Filed April '7, 1928 2 Sheets-Sheet l m mm! Fig. 3. I

Nov. 5, 1929. H. WETZLER 7 5 CASTING MACHINE Filed April 7, 1928 2 Sheets-Sheet 2 Mm Jaw 77%! Patented Nov. 5, 1929 UNITED STATES PATENT OFFICE CASTING MACHINE Application filed April 7, 1928. Serial No. 268,218, and in Germany April 14, 1927.

My invention relates to casting machines and more particularly to casting machines of the type in which castings are made which require exceptional density to be imparted to them by the casting operation or which are hard to force into the mould. It is an object of my invention to provide a machine of this type in which the mould is closed rapidly after teeming so that this operation resembles a blow, and then exerting pressure on.the part which closes the mould.

It is another object of my invention to provide suitable heating means for rapid and uniform heating of the metal and the mould and for regulating the action of such heating means as require It is still another object of my invention to so design' the complete apparatus that it is possible to operate the machine at a given moment, that is, when. the metal and the mould have been heated to the required temperature, by a part which is adapted to be actuated by slight pressure, like a trigger.

In the manufacture of castings of the kind referred to, for instance dental protheses, it is necessary to exert pressure on the mould while teeming. It has been attempted to' solve the problem by the process known as diecast-ing inwhich the metal is melted in the immediate vicinity of the mould, the melting reservoir is closed and the molten metal is ejected into the mould. The pressure requiredis generated in separate compressors, or else a part of the casting machine was designed as a compressor. Machines of this type involve the drawback of slow operation, and therefore yield a high percentage of waste, as the pressure which is under the control of a handle or lever, can not build up as rapidly as i' uired for reliable action.

Besides splashing :ften occurs upon the closing of the mould which obviously has to be effected very rapidly so that there is a tendency to force the liquid metal .forced from the mould. Splashing is eliminated in my machine by suitable dash-pot means.

The heating means for such machines must be designed so as to heat not only the metal but also the mould in the proper manner.

The burner should therefore be so designed as not only to be able to heat the mould and themetal throughout and uniformly but also adapted to be raised and lowered without being moved from the proper position with respect to the parts being heated.

The drawbacks of the old process are eliminated in my invention by the means set out above, that is rapid closing of the mould with exclusion of splashing, suitable heating and immediate operation. I In the drawings aflixed to the specification and forming part thereof a casting machine embodying my invention is illustrated diagrammatically by way of example.

In the drawings Figs. 1 and 2 are partly sectional elevations of the machine showing it in the melting and in the casting position, respectively.

Fig. 3 is a plan View and i Fig. 4 is an axial section of its burner.

eferring now to the drawings, 1 is the foundation plate of the machine, 2 and 3 are uprights extending from the foundation plate, 4 is a frame which is fulcrumed in the upright 2 at 5, and held in position on the upright 3 by a catch 6, 7 is a push bar adapted, to move in the frame 4 under the action of a spring 8 which is inserted in a cavity of the frame 4 at its upper end and with its lower end exerts downwardly directed pressure on the bar, 8' is a knurled nut on the threaded lower end of the bar which absorbs the thrust of the spring 8, 9 is a cylinder secured to the bar 7 at its lower end, 10 is a handle secured at its upper end, 11 is a catch fulcrumed on the frame 4, and 12 is a recess in the bar which is adapted to be engaged by the catch 11. p

13 is a piston which is adapted to reciprocate in the cylinder 9, 14 is a spring which tends to move the piston 13 out of the cylinder 9, 13 is a check adapted to engage a notch in the piston so as to limit its outward stroke,

16 is a bore in the top of the cylinder which connects the space 15 above the piston with the atmosphere, 17 is a central hole in the piston for admitting an extension 19 at the lower end of the bar 7, and 20 is a washer of asbestos or the like which is inserted in a depression on the face of the piston 13.

18 is a mould which is secured on the foundation plate below the cylinder 9.

21 is a partly circular burner for heating the mould 18 and for melting the metal which is placed on the mould, 23, 23 are radial nozzles extending from the burner, 22 is a tubular insertion arranged in the burner 21 and provided with nozzles to suit the nozzles 23, and 24, 25 are tubular arms for supporting the burner 21, the arm 24 supplying compressed air to the insertion 22 through suitable branch pipes 22 which are arranged in the arms 24, 25 and in a connection 26 of the two arms. Another connection 27 extends in parallel to the connection 26.

28 is a clip in which the arms 24, 25 are held, 29 is a rod on the base plate 1 on which the clip 28 is adapted to slide,.30 is a handle fulcrumed on the top of the rod 29, and 31 is a link connecting the handle with the clip 28.

As will appear from the drawings, the nozzles 23 are uniformly distributed on the burner 21 and inclined so that the issuing flames act uniformly on the mould 18 from above and on all sides. I

In operation, the bar 7 is raised and held by the catch 11 in the position Fig. 1, gas is admitted to the arm 25 at I, distributed through the connections 26, 27, and discharged.

through the nozzles 23, 23 at uniform pressure and velocity, and compressed air is admitted at II and is distributed similarly through the pipes 22', 22 and the nozzles connected with the pipe 22. In this manner the air is discharged at uniform pressure and Velocity and consequently the composition of the mixture, the combustion and the intensity of the flame will be the same at all nozzles 23. By means of the handle 30 the burner is adjusted in the proper position with respect to the mould so that the action of the heat is regulated as required.

\Vhen the mould has been properly heated and the metal has been melted, the catch 11 is moved out of the recess 12 in the bar 7 so that the bar moves down at considerable momentum under the action of its spring 8, seating the piston 13 with its washer 20 on the top of the mould 18 so that the mould is closed. The resistance of the spring 14 and of the air in the chamber 15 which flows but slowly through the bore 16 make up a dash-pot which prevents too sudden action and splashing of the metal, as the cylinder 9 is arrested in its descent until the resistance in the cylinder 9 hasbeen balanced by the momentum of the moving parts. The extension 17 depresses the central ortion of the washer 20 and generates so high a pressure above the mo ten metal in the mould that the metal is reliably forced into the mould and fills the mould completely.

Instead of the springs 8 and 14, suitable weights, pneumatic means or the like, might be provided and instead of the spring 8 means might be provided for exerting pressure on the bar 7 by hand, by a lever or any other suitable means.' Generall I wish it to be understood that I do not esire to be limited to the exact details of construction shown and described, for obvious modifications will occur to a person skilled in the art.

I claim 1. A casting machine comprising a frame, a mould on said frame, means for heating said mould, a movable part on said frame comprising a cylinder, a piston in said cylinder adapted to engage the top of said mould so as to close said mould, a pin in said cylinder adapted to penetrate through said piston and to exert pressure on the metal in said mould after said piston has closed said mould, and

means for displacing said cylinder with respect to said mould.

2. A casting machine comprising a frame, a mould on said frame, means for heating said mould, a movable part on said frame comprising a cylinder, a piston in said cylinder adapted to engage the top of said mould so as to close said mould, a packing washer on the face of said piston adapted to be caught between said piston and said mould, a pin in said cylinder adapted to penetrate through said piston to engage said member and to exert pressure on the metal in said mould after said piston has closed said mould, and means for displacing said cylinder with respect to said mould.

3. A casting machine comprising a frame, a mould on said frame, means for heating said mould, a movable part on said frame comprising a cylinder, a piston in said cylinder adapted to engage the top of said mould so as to close said mould, a pin in said cylinder adapted to penetrate through said piston and to exert pressure on the metal in said mould after said piston has closed said mould, means for displacing said cylinder with respect to said mould, and means in said cylinder for exerting resilient resistance to the inward movement of said piston in said cylinder.

4. A casting machine comprising a frame, a mould on said frame, a burner, a pipe line constituting a tubular support for said burner and connected directly to the exit of said burner, a pipe line inserted in said support and adapted to convey gas separately to the exit of said burner, and means for supplying gas to said tubular support and to said pipe line separately.

In testimony whereof I aflix my signature.

- HANS WETZLER. 

